Clojure BERT finetuning example: fix CSV parsing

[daveliepmann]

Description

Fixes CSV parsing issues raised in my PR comment. Specifically, this PR modifies the Jupyter notebook to:

• strip quotation marks from the parsed CSV file, preventing the accidental merging of separate examples
• use strict CSV parsing to surface any similar problems in the future
• remove an unused epoch def

I think this works OK for all examples. It's possible that not having quotation marks negatively affects correct performance, but if so, it would be less so than mixing up examples with each other.

Checklist

Essentials

Please feel free to remove inapplicable items for your PR.

• Changes are complete (i.e. I finished coding on this PR)

Changes

• Feature1, tests, (and when applicable, API doc)
• Feature2, tests, (and when applicable, API doc)

Comments

• If this change is a backward incompatible change, why must this change be made.
• Interesting edge cases to note here

[gigasquid]

Thanks so much @daveliepmann !